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4 SheetseSheet 1 I (No Model.)

W. F. BANKS. SW'ITGHB OABD APPARATUS. No. 588,258; Patented Aug. 17, 1897-.

WITNESSES: A I WE/lion A TTORNEYS.

(N0 oder.) 4 SheetsSheet 3.

W. F. BANKS. SWITGHBOARD APPARATUS.

No.'58 8,Z58.

WITNESSES W s ,m M 3 w m A A A %m A H d c ,B 1% E m= :v a r l 7 C P 0; Y2 .h v 3 v 1 0, w Ff G 4) ATTORNEYS.

' 20 section thereof on line 3 3 of Fig. 2.

. 45 tral-ofiice telephoneset.

UNITED STATES P TE T OFFICE.

WVALTER F. BANKS, OF MILFORD, CONNECTICUT, ASSIGNOR TO THE NATIONAL ELECTRICAL MANUFACTURING COMPANY, OF SAME PLACE.

SWITCHBOARDl APPARATUS.

SPECIFICATION forming part of Letters Patent No. 588,258, dated August 17, 1897.

' Application filed October 1, 1896. Serial No. 607,549. (No modelJ To all whom it may concern.-

Be it known that I, WALTER FREDERICK BANKS, a resident of Milford, New Haven county, State of Connecticut, have invented certain new and useful Improvements in Switchboard Apparatus, of which the following is a specification.

My invention relates to switchboard apparatus, more especially applicable to district Io telephonefcircuits.

To this end my invention consists in the special matters hereinafter pointed out and claimed.

My invention will be understood by referring to the accompanying drawings, in which-'- Figure 1 is a front elevation of a switchboard apparatus embodying rny invention. Fig. 2 is a rear elevation thereof. Fig. 3 is a Fig. 4 is a detail view of the lower row of plugs shown in Fig. 3, the'direction of view being upward. Fig. 5 is a detail diagram of the switchboardcircuits, and Fig. 6 is another arrangement 2 5 of circuits. In the drawings, A is a switchboard, which is provided with a series of line-drops D D D D D D D and a ringing-off drop R D. The board is also provided with an upper row or series of plugs or buttons B 'B 13 13 B B B whichin the present instance constitute the office-telephone-set plugs, and also with a series of plugs O C C C C C C, which in the present instance constitute thecross-connecting plugs. v

Before proceeding to describe my switchboard in detail I will state that the operation is as follows: A series of lines come into the switchboard, each of which lines terminates 40 in a line-drop. When a call comes in, the

line-drop fall's, exhibiting its number. Thereupon the appropriate office telephone set plug in the upper row ispulled out, which cuts-out the line-drop and cuts-in the cen In case the caller desires merely to converse with central no further manipulation is necessary. If, however, one caller desires to communicate with another, say 3 has called and wishes to 5o talk to 5, the operator at the desk first calls 5 and, getting aresponse from him,

pulls out C and C in the lower row and cuts his own instrument out of the line by pushing in the plugs B and B of the upper row, which he pulled out-t0 enable him to connect with 3 and 5, leaving 3 and 5 to converse, a ring-off drop being placed across the circuit by the act of joining the lines of .3 and 5.

Referring now particularly to Figs. 2, 3, and

- 4, it will be observed that below the annunciator-drops the board carries a pair of metallic strips E E". To the metallic strip E a series-of contact springs or plates 6 are electrically connected and to the metallic strip E a similar series of contact springs or plates 6' are electrically connected.

In proximity to the springs or plates 6 is a series of contact springs or plates (1, which are insulated from and somewhat longer than the springs or plates 6 e. Connected to the buttons B to B are push-rods F, which pass through guiding-braces G and, are provided with insulated blocks H, which carry metallic contact-plates h h. The contact-plates h c0- operate with the contact-springse, and the contact-plates h cooperate with the contactsprings e and d. Connected to the contactsprings 11 are the terminals of the annun ciator or line drops D to D inclusive, and bridging across from the metallic strip E to the metallic strip E is the station telephone set S, which is clearly indicated in Fig. 3. Below the metallic strips E E are metallic strips J J. Springs j are in electrical connection with the metallic strip J, and springs j are in electrical connection with the metallic strip J. A sec- 0nd and longer series of springs 12 is provided, which springs correspond in function with the springs d. Plugs similar to the plugs H are employed in connection with this lower set of springs. T K

In Fig. 5, R D is the ringing-off drop, and D is the calling or line drop' of the first line. In this figure the current enters at E a sub- 5 scribers line-terminal, and passes by the wire 1 to the contact-piece 7L. Thence it passes to the spring (1, through the callingannunciator drop D to the spring I), and thence out by the contact-piece h which corresponds on the I00 lower set of plugs to the contact-piece h on the upper set of plugs, being the upper con tact-piecc thereof, (the lower contact-piece being represented by 7t and thence by wire 2 to the terminal E". As the calling-current, say from subscriber No.- 1, passes over the eircuitjust named the drop D falls, and thereupon the operator pulls out the plug B, thereby bringing the plate 7t into contact with the spring a and the plate It into contact with the spring 6, d rawing the said contact 7t away from the spring (Z. By this means the office telephone set is cut into the subscribers line and the drop D is cut out of circuit. If the party calling wishes to communicate with another, say with B the operator pulls out the plug 0 and the plug and it being remembered that the act of pulling out any two lineplugs in the lower row on the board brings these two lines into electrical connection with the metallic strips J J it will be obvious that under this condition the-two lines are in series with each other and that since the ringing-off drop R D is bridged across from J to J provision is made for indicating a ringing-oft signal at the completion of the conversation.

Having described the modification shown in Fig. 5, I will now proceed to describe the form of arrangement of circuits shown in Fig. 6.

Referring particularly to Figs. 3, t, and 6, it will be observed that the switchboard is provided with a set of contact springs or plates 70, which are connected to each other by the wire 3, and is also provided with a set of contact-springs Z, which are mounted on the rail G, but are insulated therefrom. The plugs are also provided with contact-points m m and are adapted to contact with a spring or Z, the contact being made by the plug m with a spring when the plug is out and bythe contact 071 with the spring Z when the plug is inthat is to say, in its normal position. These two positions are clearly illustrated in Figs. 3 and 4. The contact-points m are connected togetherthat is to say, the contactpoint m of the plug Z) is connected to the contact-point 'm of the plug 0', and so on throughout the board. The contact-points m are also connected together in the same manner-that is to say, the contact-point m of the plug 1) is connected to the contact-point m of the plug a, and so on with said line throughout the board.

In Fig. 6 I have shown the contacts m as connected by wire 4 and the contacts at as connected by wire 5.

The arrangement shown in Fig. 6 is especially adapted for use in situations where a signaling-line having a battery is used as a common return for the telephone-line when the telephone is in use to transmit speech as distinguished from mere calling, the battery serving also as a calling-battery to throw the drop on the switchboard. So, therefore, in Fig. 6 I have shown a telephone-line T as running to a terminal E and a signaling-line U having a battery B therein and a connection 8 running from the said line ahead of the said battery to the terminal E and a connection 9 running from the said line behind the battery to the terminal E, the terminal E being conneeted tot-he contact Z of the upper row of plugs by a wire 0 and the terminal E being connected to the contact-points m by wire '7. By this means the battery can be employed to throw the drop to call central, and will then be cut out by the movement of the plug, so that the battery will not be in a telephone-line when the circuit is finally completed for talking. This is accomplished as follows: Supposing the parts to be in the positions shown in Fig. 6 and a call comes to the central, it passes from the telephone-line T by terminal E, wire 2, contact-plate h, contact-spring b, calling-drop D, contact-spring (I, contactplate it to contact-plate 7L4 by wire 10 to the point 11, up to which point the arrangement is identical with the arrangement shown in Fig. 5. Thence the current passes while the apparatus is in its present or normal condition by the spring 1, contact-point m, wire 5 to the other spring I and wire 0 to the terminal E thence by wire 9 and battery B to the signal-line U, forming a metallic circuit, including the battery. The operator now pulls out the plug in the upper row which corresponds to the drop which has been thrown and thereupon cuts his telephone set into the line of the caller by bringing the contact-plates h and it into contact with the springs e and 6, respectively, of his telephone set in the same manner as was done in the apparatus shown in Fig 5 and at the same time breaking the contact between m and Z and bringing 1n and k together. The condition of things is now changed and a new path from point 11 is established by wire 3, spring 7t, contact-point m, wire 7, terminal E and wire 8 to the signal-line ahead of the battery, so that the battery will not be in circuit to interfere with telephonic operations. If new the caller desires to communicate with another party on another line, he makes known his desire, and thereupon the operator at the central pulls out the two plugs in the lower row corresponding to the two lines to be connected and pushes in the plug formerly drawn out. This puts the two parties in communication with each other and leaves out the battery, the manipulations being the same as in the case just described.

Having described my invention, what I claim, and desire to secure by Letters Patent, 1s

1. In a telephone system, the combination of a plurality of contact-strips, a plurality of contact-springs e 0- connected thereto, a series of contact-strips (Z of greater length than the contact-springs c c and insulated from each other and from the contact-strips e e, a plug, contact-plates 7t 7t mounted thereon, contact-springs kl and contact-pieces m m cooperating with 70 Z.

2. In a telephone system, the combination of a plurality of subscribers lines each connected to a plurality of pairs of switchboard contact-pieces, the said pairs being arranged in sets, calling-annunciators connected across each subscribers contacts from a contact on one pair to a contact on the otherpair, a cen-- tral-office telephone set adapted for cooperation with one of the pairs, and a universal connection such as the contact-strips J and J with their contact-springs to which the second' pair of contact points of each subscrib ers line is adapted to be connected, substantially as described and forthe purposes set forth. v

3. In a switchboard apparatus, .the combination of a telephone-line and a signal-line having a battery, the said signal-line when thetelephone-line is in use, forming a common return for the telephone-line so that the signal-line and telephone-line constitute a metallic circuit, a central station having a contact for each telephone-line, a plurality of outgoing terminals at central, one terminal being connected ahead of the battery at the central station and the other terminal being connected behind the battery at the central station and contact devices in circuit with the said plurality of outgoing terminals, and

a switching device at the central station for switching the connection of the telephone-line from one side of the battery to the other.

4. In a telephone-switchboard apparatus, the combination of a telephone-line running to a central station and a signaling-line also running to the central station and having a battery at central, the said signalingline forming a common return for the telephoneline, a contact for each telephone-line at the central, a plurality of outgoing terminals at the central, one terminal being connected to having a battery and forming a common re-' turn for the telephone-line when the said telephone-line isin use for transmitting speech as distinguished from calling, so that the calling-line and the telephone-line are included in the same talking-circuit, a plurality of outgoing terminals atthe central, one terminal being connected to the calling-line at the central station ahead of the battery in the said calling-line and the other terminal being connected to the calling-line at the central station behind the battery in the said callingline and a switching device or plug for connecting the telephone-line with one or the other of the outgoing terminals, whereby acall may be received at the central station over the telephone and calling line and by manipulating the plug or switch the telephone-line may be thereupon connected to the calling-line so as to cut the battery out of the telephone talking-circuit.

WALTER F. BANKS. Witnesses:

GEO. EtMoasn, MAURIcE BLOCK. 

